Cryptosphaeria eunomia

Cryptosphaeria eunomia is an ascomycete fungus recognized for causing bark and wood necrosis in various deciduous tree species. This pathogen is frequently identified as a factor contributing to stem canker formation, which can significantly weaken the structural integrity of the affected host tree.

The primary hosts of this fungus typically include alder (Alnus) and other hardwood species found in both natural forests and managed landscapes. While it often acts as a saprophyte on dead organic matter, it functions as a facultative parasite that exploits weakened trees, often following environmental stress or physical wounding.

Symptoms of the disease are characterized by sunken necrotic patches on the bark, accompanied by longitudinal cracking. As the fungal stroma develops, small, dark, pimple-like structures appear on the bark surface. These lesions disrupt the vascular system, frequently resulting in chlorosis, dieback of branches, and in severe cases, tree mortality.

The development and spread of the pathogen are highly dependent on environmental moisture levels and the presence of bark injuries. Fungal spores are disseminated via wind and rain splashes, particularly during the dormant season or early spring, allowing the pathogen to enter through cracks and wounds in the bark surface.

• Rigorous sanitation pruning of dead or infected branches.
• Application of antifungal wound dressings to fresh cuts or injuries.
• Improvement of site conditions to enhance tree vigor and immune response.
• Systematic removal of severely infected host trees from affected stands.

The overall impact of Cryptosphaeria eunomia is manifested in the progressive degradation of the tree crown and the reduction of the commercial value of the timber. Effective prevention is crucial in silviculture, as the disease can rapidly compromise the health of entire stands if left unmanaged, leading to long-term silvicultural losses.